Dallas Cowboys' Tony Romo (9) hands off to DeMarco Murray (29) during an NFL football game against the Chicago Bears Monday, Oct. 1, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Photo By LM Otero/Associated Press

Dallas Cowboys' Tony Romo (9) hands off to DeMarco Murray (29) in the first half of an NFL football game Monday, Oct. 1, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Photo By Jerry Lara/Express-News

Dallas Cowboys's running back DeMarco Murray runs down the sideline as Tampa Bay Buccaneers' Michael Bennett tries to push him out of bounds during the first half at Cowboys Stadium in Arlington, Texas, Sunday Sept. 23, 2012.

Photo By Tim Sharp/Associated Press

Dallas Cowboys running back DeMarco Murray (29) finds open field during the second half of an NFL football game against the Tampa Bay Buccaneers, Sunday, Sept. 23, 2012 in Arlington, Texas. (AP Photo/Tim Sharp)

Photo By Kevin P. Casey/Associated Press

Dallas Cowboys' DeMarco Murray in action against the Seattle Seahawks in the first half of an NFL football game, Sunday, Sept. 16, 2012, in Seattle. (AP Photo/Kevin P. Casey)

Photo By John Froschauer/Associated Press

Dallas Cowboys' DeMarco Murray sits on the bench in the final minutes in the second half of an NFL football game against the Seattle Seahawks, Sunday, Sept. 16, 2012, in Seattle. The Seahawks won 27-7. (AP Photo/John Froschauer)

Photo By John Froschauer/Associated Press

Dallas Cowboys Tony Romo makes a pass to DeMarco Murray against the Seattle Seahawks in the first half of an NFL football game, Sunday, Sept. 16, 2012, in Seattle. (AP Photo/John Froschauer)

Dallas Cowboys running back DeMarco Murray (29) rushes past New York Giants linebacker Chase Blackburn (93) for a 48-yard gain during the third quarter of an NFL football game, Wednesday, Sept. 5, 2012, in East Rutherford, N.J. The Cowboys won 24-17. (AP Photo/Julio Cortez)

Photo By Bill Kostroun/Associated Press

New York Giants' Antrel Rolle, top, tackles Dallas Cowboys' DeMarco Murray during the second half of an NFL football game Wednesday, Sept. 5, 2012, in East Rutherford, N.J. (AP Photo/Bill Kostroun)

Photo By Julio Cortez/Associated Press

Dallas Cowboys running back DeMarco Murray runs with the ball against the New York Giants during the first half of an NFL football game Wednesday, Sept. 5, 2012, in East Rutherford, N.J. (AP Photo/Julio Cortez)

It's unknown if he'll play Sunday night against Philadelphia, and whether his six-game absence is what ails the Cowboys' running game.

Murray was a limited participant in practice Wednesday and Thursday in what coach Jason Garrett said was the most football work the second-year pro has done since spraining his right foot against Baltimore on Oct. 14.

Murray declined interviews after both practices, but did acknowledge a “good first day” in a playful exchange with reporters Wednesday.

“If he's ready to go, it will be a boost,” quarterback Tony Romo said. “If not, some guys will have to continue to step up.”

The question is whether it's a coincidence the Cowboys have rushed for more than 100 yards only once — and only 101 at that — in six games without Murray, who had a franchise-record 253 yards in his first start as a rookie last season and averaged 5.5 yards per carry.

This year, he had three straight games with a per-carry average under 4 yards before getting 90 and injuring his foot in the first half against the Ravens. He had one 3-yard carry after halftime before going to the sideline for good, and the Cowboys have been on a steady slide to last in the league in rushing ever since.

“I'm hopeful,” offensive line coach Bill Callahan said. “When he comes back, we'll see how he feels and see where it all is.”

Felix Jones has seen most of the work in Murray's absence, but he's been slowed by injuries to both knees. Jones is averaging a career-low 3.6 yards per carry.

There was a chance undrafted rookie Lance Dunbar would start last week against Washington, but Jones managed to stay in the lineup. It didn't matter much after the Cowboys fell behind 28-3 in the first half and had only two rushing attempts in the second half. Jones finished with 14 yards on six carries.

Jones missed practice when Murray returned Wednesday, but he was back on the field as a limited participant Thursday.